I've managed to confuse myself totally. i have 2 under counter light, both take 6 AAA 1.5V batteries (12 in total) with batteries https://lh3.googleusercontent.com/-n8iOn2-B-hU/UYIvsI-c7eI/AAAAAAAAB5A/x2JPA9bw12k/w571-h428-p-o/20130502_101349.jpg[/img[ Without batteries [img]https://lh5.googleusercontent.com/-ZbOr2T0HsCM/UYIvR2Kb5AI/AAAAAAAAB44/uTYSvwyYHo4/w571-h428-p-o/20130502_101428.jpg i have a powered USB hub next to both of them. can i use 1 USB port to power both sets of lights? and if so how? as a USB is 5V DC, and these lights are 9V DC each, split into 2 lots of 4.5v. i was thinking of putting them in parrellel x 4 with a resistor (value to be determined). in my mind that works. what do you say? help, its costing me a fortune in batteries to light up my desk
Hi MonkeyTurnip, I do not understand what you mean by : 'these lights are 9V DC each, split into 2 lots of 4.5v'. If this light needs 9V, you cannot use the USB. If there are two lights and each use 4.5V, you can use the USB port. I would imagine it can be powered directly by the 5V, no need for any resistors - a difference of 0.5V won't do any damage. Bear in mind the max. current output of USB is 500mA. There is another two alternatives - do as what Saspro mentioned or switch to chargeables (light might be slightly dimmer as each battery is 1.2V.
